The conventional foldable electronic devices, such as a foldable display, mainly connects the sides of the support members of display units through a split shaft or a multi-axis shaft to form a pivoting connection, thereby making the flexible display or each display unit folded or unfolded. Since the current electronic devices are mainly designed to be thinner in order to be carried by users, the spacing between two bodies that can be reserved for the hinge would become narrower and narrower, and the dimensional requirements for the hinge are bound to be reduced. For example, the Chinese Patent entitled with “A Foldable display” with No. CN105788452A has disclosed a foldable structure of a hinge, which mainly has a first body and a third body of the hinge respectively connected to a first supporting member and a second supporting member, and has the first supporting member and the second supporting member combined with a flexible display module. Thus, the flexible display module on the first supporting member and the second supporting member are folded after the first body and the third body are turned relative to the second body. However, the first body and the third body of the hinge foldable structure mentioned above are turned with reference to the two ends of the second body. Since it is necessary to provide a structure on the second body that allows the first and third bodies to turn, the spacing between the two bodies that can be reserved for the hinge cannot be effectively reduced.
As shown in the three patents of CN103576775A, CN106205385A and U.S. Pat. No. 9,250,733B, the two bodies are formed in a relatively foldable manner by a biaxial shaft or an approximately biaxial-shaft structure. The “support structure” in these three patents has its one end therein pivoted and the other end movable. When the entire “foldable device” is folded, each supporting structure in the two bodies is driven by another force exerting member, for example, spring, tension spring, magnetic iron, and torsion spring so as to form an accommodation space therein for accommodating the curved center of the flexible display, and the unfolded center of the flexible display is supported by the respective support structures when the entire foldable device is unfolded.